Are LED Transilluminators Better than UV Transilluminators?

UV transilluminators are commonly used in science laboratories to facilitate the optimum visualization of proteins, nucleic acids (DNA and RNA) and their precursors following a gel electrophoresis procedure. This device typically consists of a UV light source, optical filters, and associated electronics which are housed in a specialized stainless steel box. UV transilluminators are also equipped with an appropriate UV blocking cover to protect the user from potentially hazardous UV exposure.

UV transilluminators work by emitting high levels of UV radiation through the viewing surface where the wet agarose gels are placed. Since the gels are previously stained with a fluorescent dye which binds to the nucleic acid, exposing them to a UV light source causes the dye to fluoresce. This makes even the faintest bands visible to the naked eye or with the aid of an appropriate imaging system.

The Dangers of Using UV Transilluminators

While this technique proves to be quite useful in applications that require the viewing of the sample (i.e. sizing a PCR product, quantifying or purifying a DNA segment, or verifying DNA integrity following extraction), studies prove that the use of such a device exposes operators to dangerously high levels of UV radiation (Journal of Occupational and Environmental Hygiene, 2005).

It has long been established that UV radiation is a major mutagenic agent and overexposure to such factors facilitates premature skin aging and increases the risk of skin damage (e.g. actinic keratoses), skin cancer (melanoma and non-melanoma skin cancer such as basal and squamous cell carcinomas), cataracts and other eye damage (pterygium, macula degeneration). Overexposure to UV radiation may also compromise the proper functioning of the immune system and lower the body’s natural defenses.

Taking all these things into consideration, operators are advised to undergo special safety training or “use automation, substitution, isolation, shielding and/or personal protective equipment” to control exposure when using a UV transilluminator.

Why Use LED Transilluminators?

Aside from the potential health risks involved, using UV light also increases the risk of damaging the nucleic acids (DNA, RNA) through nicking and crosslinking, and may significantly reduce the cloning efficiency. For these reasons, using an alternative non-UV system such as an LED transilluminator is highly recommended.

LED transilluminators also offer several other advantages over UV transilluminators. Here are some of them:

• By using an LED transilluminator, you can do away with ethidium bromide, a highly toxic chemical and mutagenic agent.
• Using a high purity LED light source in visualizing your proteins and nucleic acids produces strong contrast which provides greater image clarity and allows for direct visualization of the samples.
• LED transilluminators use high performance LED lights that provide unprecedented light uniformity for a more even illumination across the table.
• These devices use significantly lower operating voltage. On the other hand, UV transilluminators require 1 kV and even more.
• The intensity of LED lights can easily be adjusted in the range of 0% to 100% to suit your intended application. You can’t possibly do this if you are using a UV transilluminator.
• LED light sources provide a narrow band of UV centered at about 302nm or 365 nm. Since wavelengths below 380nm do not reach the retina, using LED transilluminators are typically eye-safe and will not burn your skin.

Tips in Choosing an LED Transilluminator

Without a doubt, LED transilluminators are a much better choice than UV transilluminators. If you are thinking about buying one for your lab, then here are some things you may want to consider:

• Surface size. Consider the viewing surface size since you may be working with varying size gels.
• Wavelengths. Some models come in single or dual wavelengths.
• Dimensions of the bench top unit.